Cold-water geyser

Cold-water geysers look quite similar to their steam-driven counterparts; however, their CO2-laden water often appears whiter and more frothy.

The more familiar hot-water geysers derive the energy for their eruptons from the proximity to (relatively) near-surface magma.

The magnitude and frequency of such eruptions depend on various factors such as plumbing depth, CO2 concentrations and refresh rate, aquifer water yield, etc.

A borehole drilled for a well, for example, can unexpectedly provide an escape route for the pressurized water and CO2 to reach the surface.

When the pressure decreases due to the widening of a fissure, the CO2 bubbles expand, and that expansion displaces the water above and causes the eruption.